The development of argumentation support systems for different types of groups and application areas has been receiving growing interest in the last twenty years. Such systems address the needs of a user to interpret and reason about knowledge during a discourse, and demonstrate diverse human and machine reasoning functionalities. However, methodologies to check whether the reasoning mechanisms of such systems adhere to broadly accepted argumentation theories are missing. Provision of such methodologies is of much value, especially in data intensive contexts. The approach described in this paper is a first step towards this direction. Specifically, we formally assess a specific argumentation support system, namely HERMES, against Dungs argumentation theory and prove its correctness as far as the acceptability of arguments is concerned.